This study investigates the relative importance of intonational versus syntactic features in children's comprehension of language. The research employed a methodology in which a sentence was presented orally just prior to a tachistoscopic presentation of a picture in which various components were misrepresented. Subjects were 30 children at each of three grade levels (2, 5, and 9). Besides age differences, the variables under investigation were: (1) whether the misrepresentation involved the presupposed or the asserted proposition, and (2) whether the presupposition was indicated in surface structure by intonation or by syntactic structure. The finding that there was an interaction between age and manner of making presupposition is discussed in detail. It is clearly demonstrated that intonational features are important until relatively late in the developmental course of language acquisition and the shift to sensitivity to syntactic structure occurs during a period when language development is assumed to be complete. The effect of acquisition of reading skills is considered as a possible means of accounting for these findings. (DP)